The UK electoral reform referendum

In a referendum on May 5, voters in the UK will decide whether to adopt the alternative vote (AV) system, or retain the present “first past the post” method of electing members of parliament. Our interactive feature explains the differences between the two voting systems and shows how the result of the 2010 general election might have been different had it been contested under the AV system.

Source: The projections shown on the map are based on research conducted by political scientists at the University of Essex using data collected by the British Election Study immediately after the May 2010 general election.